192 
THE ART OF REARING 
the laboratory, may instantly harden, more or less, 
the silky substance of those worms on which it 
may blow. This substance thus not being fit to 
pass through the silk-spinning tubes, the insect is 
soon obliged to cease drawing out its cocoon, and 
/suffers. Then will many of those worms that are 
not sufficiently wrapt in the silk be liable to drop 
off at any moment, and lessen the abundance of 
cocoons. To be convinced of this, it is only 
necessary to make the following experiment : — 
Cover several small fagots with paper, when they 
are loaded with cocoons, being careful to place 
the paper only between the second and third 
fagot, the fourth and fifth, and the sixth and 
seventh, and so on : doing this on the side ex- 
posed to the blast and agitation of the air, it will 
be found, that on those fagots that are sheltered 
from the air by the paper, the cocoons will be 
fine, full, and numerous; whilst on the exposed 
fagots there will be few cocoons, the worms 
having dropped off, gone elsewhere, or formed 
bad cocoons. 
2nd. Too damp an atmosphere, preventing the 
contraction of the skin ofi*.he worm, — which ena- 
bles it to evacuate the last excrement, and to exude 
the silk through the silk-drawing tubes, — causes 
them to suffer, weakens them, slackens their 
work, and gives them numerous disorder’s which 
cannot easily be defined. 
